Femoral trial component

ABSTRACT

An orthopaedic surgical instrument including a femoral trial component configured to be coupled to a surgically-prepared distal end of a patient&#39;s femur. The femoral trial component has a fixation side configured to engage a posterior aspect of the surgically-prepared distal femur.

This application claims priority under 35 U.S.C. §120 to U.S. patentapplication Ser. No. 13/731,575, which was filed on Dec. 31, 2012 andwhich claimed priority under 35 U.S.C. §120 to U.S. patent applicationSer. No. 13/530,239, which was filed on Jun. 22, 2012 and which claimedpriority under 35 U.S.C. §119 to U.S. Patent Application No. 61/503,237,which was filed on Jun. 30, 2011. Each of these applications areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to surgical instruments used on apatient's femur.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.A typical knee prosthesis includes a tibial tray, a femoral component,and a polymer insert or bearing positioned between the tibial tray andthe femoral component. Femoral components are designed to be attached toa surgically-prepared distal end of a patient's femur. Tibial trays aredesigned to be attached to a surgically-prepared proximal end of apatient's tibia.

To facilitate the replacement of the natural joint with the kneeprosthesis, orthopaedic surgeons use a variety of orthopaedic surgicalinstruments such as, for example, prosthetic trial components, cuttingblocks, drill guides, milling guides, and other surgical instruments.Prosthetic trial components, such as, for example, a femoral trialcomponent and a tibial bearing trial component, are used to size andselect the components of the knee prosthesis that will replace thepatient's natural joint. A procedure that utilizes the trial componentsto size and select the components of the knee prosthesis is oftenreferred to as a trial reduction.

SUMMARY

According to one aspect of the disclosure, an orthopaedic surgicalinstrument includes a polymeric femoral trial component configured to becoupled to a surgically-prepared distal end of a patient's femur. Thefemoral trial component includes an articular side having a posteriorfemoral condyle surface and a fixation side that is opposite thearticular side. The fixation side has a plurality of ribs that extend ina direction away from the articular side so as to define a plurality ofpockets therebetween. Each rib has an outer surface, and the outersurfaces of the ribs define a posterior fixation surface that extendsgenerally in the superior/inferior direction and is configured to matchthe surgically-prepared distal end of the patient's femur. The femoraltrial component also includes a plurality of teeth extending from theposterior fixation surface in a direction away from the articular side.Each tooth of the plurality of teeth has a pointed tip that defines alongitudinal axis of the tooth extending in the medial/lateraldirection.

In some embodiments, each tooth of the plurality of teeth may have atriangular cross-section. In some embodiments, the plurality of teethmay include at least four teeth.

Additionally, in some embodiments, the polymeric femoral trial componentmay be formed as a molded integral component. In some embodiments, theouter surfaces of a number of the plurality of ribs may further define adistal fixation surface extending generally in the anterior/posteriordirection and a posterior-chamfer fixation surface extending superiorlyand posteriorly from the distal fixation surface to the posteriorfixation surface.

In some embodiments, a second plurality of pockets may be defined ineach of the distal fixation surface and the posterior-chamfer fixationsurface between the plurality of ribs. In some embodiments, the femoraltrial component may have an aperture defined in the distal fixationsurface, and the aperture may extend from the fixation side to thearticular side.

Additionally, in some embodiments, the femoral trial component mayfurther include a lateral posterior condyle including the articular sideand the fixation side that is opposite the articular side, and a medialposterior condyle. The medial posterior condyle may include a secondarticular side including a second posterior femoral condyle surface anda second fixation side that is opposite the second articular side. Thesecond fixation side may have a second plurality of ribs that extend ina direction away from the second articular side so as to define a secondplurality of pockets therebetween. Each rib may have an outer surfaceand the outer surfaces of the ribs may define a second posteriorfixation surface that extends generally in the superior/inferiordirection and is configured to match the surgically-prepared distal endof the patient's femur. The medial posterior condyle may also include asecond plurality of teeth extending from the posterior fixation surfacein a direction away from the second articular side.

In some embodiments, the femoral trial component may further have amedial side and a lateral side. The medial side may have at least onenotch defined therein extending from the fixation side to the articularside, and the lateral side may have at least one notch defined thereinextending from the fixation side to the articular side.

In some embodiments, the medial side may include two notches, and thelateral side may include two notches.

According to another aspect, an orthopaedic surgical instrument includesa polymeric femoral trial component configured to be coupled to asurgically-prepared distal end of a patient's femur. The femoral trialcomponent includes an articular side having a posterior femoral condylesurface and a fixation side that is opposite the articular side. Thefixation side has a planar posterior fixation surface that extendsgenerally in the superior/inferior direction and is configured to matchthe surgically-prepared distal end of the patient's femur. A pluralityof teeth extend from the planar posterior fixation surface in adirection away from the articular side. Each tooth has a pointed tipthat defines a longitudinal axis of the tooth extending in themedial/lateral direction.

In some embodiments, a plurality of pockets may be defined in the planarposterior fixation surface between the plurality of teeth.

According to another aspect, an orthopaedic surgical instrument includesa polymeric femoral trial component configured to be coupled to asurgically-prepared distal end of a patient's femur. The femoral trialcomponent has a medial side, a lateral side, an articular side includinga posterior femoral condyle surface, and a fixation side that isopposite the articular side. The fixation side is configured to engage aposterior aspect of the surgically-prepared distal femur. The polymericfemoral trial component also includes a first notch extending from thefixation side to the articular side that is defined in the medial side,and a second notch extending from the fixation side to the articularside that is defined in the lateral side.

In some embodiments, the fixation side may include a plurality of ribs.Each rib may have an outer surface and the outer surfaces may define aposterior fixation surface extending generally in the superior/inferiordirection that is configured to match the surgically-prepared distal endof the patient's femur. A plurality of teeth may extend from theposterior fixation surface in a direction away from the articular side.In some embodiments, the plurality of teeth may include at least fourteeth.

Additionally, in some embodiments, each tooth of the plurality of teethmay have a pointed tip that defines a longitudinal axis of the toothextending in the medial/lateral direction. In some embodiments, thefemoral trial component may be formed as a molded integral component. Insome embodiments, each tooth of the plurality of teeth may have atriangular cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of an orthopaedic surgical instrumentassembly;

FIG. 2 is an exploded perspective view of the orthopaedic surgicalinstrument assembly of FIG. 1;

FIG. 3 is a perspective view of the femoral trial component of theorthopaedic surgical instrument assembly of FIG. 1;

FIG. 4 is a sagittal cross sectional view of the femoral trial componentof FIGS. 1-3;

FIG. 5 is a bottom plan view of the femoral trial component of FIGS.1-4;

FIG. 6 is a perspective view of the femoral trial component of FIGS. 1-5positioned on a surgically-prepared distal end of a patient's femur;

FIG. 7 is a sagittal cross sectional view of the femoral trial componentof FIGS. 1-6 on the surgically-prepared distal end of the patient'sfemur;

FIG. 8 is a perspective view of the orthopaedic surgical instrumentassembly of FIG. 1 positioned on surgically-prepared ends of thepatient's femur and tibia with the patient's knee in extension; and

FIG. 9 is a perspective view of the orthopaedic surgical instrumentassembly of FIG. 8 with the patient's knee in flexion.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants and surgicalinstruments described herein as well as in reference to the patient'snatural anatomy. Such terms have well-understood meanings in both thestudy of anatomy and the field of orthopaedics. Use of such anatomicalreference terms in the written description and claims is intended to beconsistent with their well-understood meanings unless noted otherwise.

Referring to FIGS. 1-4, an orthopaedic surgical instrument assembly 10is shown. The orthopaedic surgical instrument assembly 10 has a numberof trial components 12, including a femoral trial 14, a tibial basetrial 16, and a tibial bearing trial 18. The femoral trial 14 isconfigured to be secured to a surgically-prepared end of a patient'sdistal femur 20 (see FIG. 6), whereas the tibial base trial 16 isconfigured to be secured to a surgically-prepared end of a patient'sproximal tibia 22 (see FIG. 8).

As shown in FIG. 2, the tibial base trial 16 includes a plate 30 havingan opening 32 defined therein sized to receive a base insert 34. Thebase insert 34 includes a body 36 having a number of fixation pins 38extending away from a lower surface 40 of the body 36. The base insert34 also includes a post 42 extending away from an upper surface 44 ofthe body 36. It should be appreciated that in other embodiments thefixation pins 38 may be omitted from base insert 34 or additionalfixation pins 38 may be added.

The tibial bearing trial 18 is configured to assist the surgeon inselecting a prosthetic tibial bearing component of a typical kneeprosthesis. The tibial bearing trial 18 is a multi-piece assembly thatincludes a bearing surface trial 46 and a shim 48. The post 42 of thebase insert 34 is received in an opening 50 defined in the shim 48 andan opening (not shown) defined in the lower surface of the bearingsurface trial 46. The bearing surface trial 46 includes a lateralarticular surface 52 and a medial articular surface 54 positionedopposite the lower surface. In the illustrative embodiment, the bearingsurface trial 46 is embodied as a fixed bearing trial and is fixedrelative to the tibial base trial 16 (i.e., it is configured to notsubstantially rotate or move in the anterior/posterior direction ormedial/lateral direction). In other embodiments, the bearing surfacetrial 46 may be a mobile bearing trial configured to rotate relative tothe tibial base trial 16. As shown in the illustrative embodiment, thetibial bearing trial 18 is a multi-piece assembly, but it should beappreciated that in other embodiments the tibial bearing trial 18 may bea single monolithic component. One example of a tibial bearing trial 18is shown and described in co-pending U.S. Patent Application Ser. No.61/503,300, entitled “TRIALING SYSTEM FOR A KNEE PROSTHESIS AND METHODOF USE” by Thomas E. Wogoman et al. (Attorney Docket No. 265280-210420,DEP6286USPSP), which is incorporated herein by reference.

The femoral trial 14 of the orthopaedic surgical instrument assembly 10is configured to assist the surgeon in selecting a femoral prostheticcomponent, which will emulate the configuration of the patient's naturalfemoral condyles. As such, the femoral trial 14 includes a lateralcondyle surface 56 and a medial condyle surface 58, which may be shaped(i.e., curved) in a manner that approximates the condyles of the naturalfemur. The lateral condyle surface 56 and the medial condyle surface 58are spaced apart from one another, thereby defining an intercondylarnotch 60 therebetween. The articular surfaces 52, 54 of the tibialbearing trial 18 are configured to rotate with the lateral condylesurface 56 and the medial condyle surface 58, respectively, of thefemoral trial 14.

As shown in FIG. 3, the lateral condyle surface 56 and the medialcondyle surface 58 are formed in an articular side 62 of the femoraltrial 14. A fixation side 64, which is the side of the femoral trial 14that contacts the surgically-prepared distal femur of the patient, isopposite the articular side 62. The fixation side 64 includes aplurality of ribs 66 that extend in a direction away from the articularside 62. Each of the ribs 66 includes an outer surface 68, and the outersurfaces 68 of the ribs 66 cooperate to define multiple surfaces of thefixation side 64. Those surfaces, identified below as “fixationsurfaces,” mate or match with planar surfaces surgically cut into thepatient's femur, as discussed in greater detail below.

Although the femoral trial 14 is illustratively shown as a singleintegral or monolithic component, the trial 14 is characterized hereinby a number of “regions” or “structures.” For example, the anteriorstructure of the femoral trial 14 is referred to herein as an anteriorflange 70. Moving along the femoral trial 14 from an anterior toposterior, the anterior flange 70 transitions to an anterior-chamferregion 72, which transitions to a distal condylar region 74. The distalcondylar region 74 transitions to a posterior-chamfer region 76. A pairof femoral condyles 78 forms the posterior structure of the femoraltrial 14. One of the femoral condyles 78 is medially positioned and theother laterally positioned when the femoral trial 14 is attached to thedistal end of the patient's resected femur 20 depending on which knee isbeing replaced.

The outer surfaces 68 of the ribs 66 of each of the posterior femoralcondyles 78 define a planar posterior fixation surface 82 on thefixation side 64, with one of the posterior fixation surfaces 82 beingthe lateral fixation surface and the other medial fixation surface. Eachposterior fixation surface 82 is positioned opposite a posterior condylesurface 84 on the articulation side 60. As shown in FIG. 4, theposterior fixation surfaces 82 and the posterior condyle surfaces 84extend generally in the superior/inferior direction.

The outer surfaces 68 of the ribs 66 of the distal condylar region 74define a pair of planar distal fixation surfaces 86 (one being mediallypositioned, the other laterally positioned). Each of the distal fixationsurfaces 86 is opposite a distal condyle surface 88. As shown in FIG. 3,the distal fixation surfaces 86 extend generally in theanterior/posterior direction.

The distal condylar region 74 also includes a pair of apertures orthrough-holes 90, one of which is positioned laterally while the otheris positioned medially. Each through-hole 90 extends from an opening 92defined in one of the distal fixation surfaces 86 to an opening 94defined in the corresponding distal condyle surface 88. Eachthrough-hole 90 is sized to receive a surgical drill, as described ingreater detail below.

The posterior-chamfer region 76 of the femoral trial 14 includes a pairof planar posterior-chamfer fixation surfaces 96 defined by the outersurfaces 68 of the ribs 66, with one being medially positioned and theother laterally positioned. The lateral and medial posterior-chamferfixation surfaces 96 extend superiorly and posteriorly from theirrespective lateral and medial distal fixation surfaces 86 to theirrespective posterior fixation surfaces 82. Each of the posterior-chamferfixation surfaces 96 is positioned opposite a posterior-chamfer condylesurface 98.

Similarly, the anterior-chamfer region 72 includes a pair of planaranterior-chamfer fixation surfaces 100. Each anterior-chamfer fixationsurface 100 is positioned opposite an anterior-chamfer condyle surface102. The anterior-chamfer fixation surfaces 100 extend superiorly andanteriorly away from their respective lateral and medial distal fixationsurfaces 86 to a planar anterior fixation surface 104 of the anteriorflange 70. The anterior fixation surface 104 is opposite an anteriorcondyle surface 106, and, like the posterior fixation surfaces 82, theanterior fixation surface 104 extends generally in the superior/inferiordirection.

The plurality of ribs 66 define a plurality of pockets 108 in each ofthe fixation surfaces 82, 86, 96, 100, and 104. In the illustrativeembodiment, the pockets 108 are separated such that none of the pocketsare in fluid communication with each other. It should be appreciatedthat in other embodiments two or more pockets may be in communicationwith one another such that a single, continuous pocket is formed in thefixation side 72 of the femoral trial 14. It will be appreciated that inother embodiments the pockets 108 may be omitted from one or more of thefixation surfaces.

The femoral trial 14 of the orthopaedic surgical instrument assembly 10includes a plurality of teeth 110 that extend from each of the posteriorfixation surfaces 82 in a direction away from the articular side 62. Theteeth 110 are configured to engage or grip the surgically-prepareddistal end of the patient's femur 20 when the femoral trial 14 iscoupled thereto. The illustrative teeth 110 extend parallel to eachother in the medial/lateral direction. It should be appreciated that inother embodiments the teeth 110 may be angled relative to each other orarranged in various patterns on the posterior fixation surfaces 82.Additionally, one or more of the teeth 110 may extendinferiorly/superiorly along the posterior fixation surface 82 inaddition to, or instead of, extending medially/laterally as shown inFIGS. 3-4. It should also be appreciated that in other embodiments oneor more teeth may be formed on any of the other surfaces 82, 86, 96,100, and 104 of the fixation side 64 of the femoral trial 14.

As shown in FIG. 4, each tooth 110 has a triangular cross section whenviewed in the sagittal plane. It should be appreciated that in otherembodiments the teeth 110 may have a square cross section, rectangularcross section, dome-shaped cross section, or any other cross sectionsuitable to engage the surgically-prepared distal end of the patient'sfemur 20. Additionally, while the teeth 110 have the same cross sectionin the illustrative embodiment, it should be appreciated that in otherembodiments each tooth 110 may have a unique cross section.

Each tooth 110 has a body 112 including a base 114 fixed to theposterior fixation surface 82 between one or more of the pockets 108.The body 112 extends outwardly from the posterior fixation surface 82 toa tip 116. The tip 116 defines a longitudinal axis 122 of each tooth 110extending in the medial/lateral direction. The tip 116 of each body 112is spaced apart from the posterior fixation surface 82 such that eachtooth 110 has a height 120. In the illustrative embodiment, the height120 is approximately 0.38 millimeters. However, in other embodiments,the height 120 may be greater than that shown in the illustrativeembodiment. Additionally, while each tooth 110 has the same height 120in the illustrative embodiment, it should be appreciated that in otherembodiments the height 120 of each tooth 110 may vary.

The femoral trial 14 also includes a pair of sidewalls 124, 126 thatextend between the articular side 62 and the fixation side 64, with onesidewall being medially positioned and the other laterally positioneddepending on which knee is being replaced. As shown in FIG. 5, each ofthe sidewalls 124, 126 has a pair of notches 128, 130 defined therein.The notch 128 extends between the articular side 62 and the fixationside 64 of the distal condylar region 74 and has a base surface 132 thatconnects the distal fixation surface 86 to the distal condyle surface88. Similarly, the notch 130 extends between the articular side 62 andthe fixation side 64 of the distal condylar region 74 and theanterior-chamfer region 72. The notch 130 includes a base surface 134that connects the distal fixation surface 86 to the distal condylesurface 88, and a base surface 136 that connects the anterior-chamferfixation surface 100 and the anterior-chamfer condyle surface 102. Inthe illustrative embodiment, the notches 128, 130 extend inwardlyapproximately 1.75 millimeters from the sidewalls 124, 126,respectively, to the base surfaces 132, 134, 136.

The sidewalls 124, 126 define an outer edge 138 of the femoral trial 14corresponding to a standard femoral prosthetic component size. The basesurfaces 132, 134, 136 of the notches 128, 130 define another edge 140of the femoral trial 14 corresponding to a standard, but more narrow,femoral prosthetic component size. As such, a single femoral trial 14may be used to size multiple femoral prosthetic component sizes. Itshould be appreciated that in other embodiments one or more of thenotches 128, 130 may be omitted from the femoral trial 14. It shouldalso be appreciated that in other embodiments the position of thenotches 128, 130 along the sidewalls 124, 126 may vary such that, forexample, the notches 130 are formed entirely in the distal condylarregion 74.

The femoral trial 14 is constructed from a polymeric material. In theillustrative embodiment, the polymeric material is a fifty percentglass-reinforced nylon. Another polymeric material that may be used isthirty percent glass-filled polyether ether ketone (PEEK) orpolyethylene, such as ultrahigh molecular weight polyethylene (UHMWPE),although other biocompatible polymers may be used. The tibial bearingtrial 18 may be constructed from a material, such as, for example, anyof the polymeric materials described above, which permits smootharticulation between the tibial bearing trial 18 and the femoral trial14. The tibial base trial 16 and the base insert 34 may be constructedfrom a biocompatible metal, such as a cobalt chrome alloy; othermaterials, such as ceramics, may also be used.

Referring now to FIGS. 6-9, the orthopaedic surgical instrument assembly10 is shown in use with the patient's bony anatomy. As shown in FIG. 6,a surgically-prepared distal end 200 of the patient's femur 20 includesa resected medial condyle 202 and a resected lateral condyle 204. Inuse, the surgeon positions the femoral trial 14 over the distal end 200of the patient's femur 20. An impactor assembly 206 may be used toimpact the femoral trial 14 into the distal end 200.

To do so, an engagement end 208 of the impactor assembly 206 ispositioned in contact with the articular side 62 of the femoral trial14, and force is applied to the impactor assembly 206 until the fixationside 64 of the femoral trial 14 contacts the resected medial condyle 202and the resected lateral condyle 204. Once the femoral trial 14 isproperly positioned on the distal end 200 of the patient's femur 20, thesurgeon may remove the impactor assembly 206. It should be appreciatedthat in other embodiments the surgeon may position the femoral trial 14on the distal end 200 of the patient's femur 20 by hand without usingthe impactor assembly 206.

When the femoral trial 14 is positioned on the distal end 200 of thepatient's femur 20, the sidewalls 124, 126 indicate where the outer edgeof the standard femoral prosthetic component would be located on theresected medial condyle 202 and the resected lateral condyle 204.Conversely, the base surfaces 132, 134, 136 of the notches 128, 130 inthe femoral trial 14 indicate where the outer edge of the narrow femoralprosthetic component would be located. If the sidewalls 124, 126 extendbeyond the resected medial condyle 202 and the resected lateral condyle204 of the distal end 200 of the patient's femur 20, the surgeon mayselect the narrow femoral prosthetic component for implantation.

The resected medial condyle 202 and the resected lateral condyle 204 ofthe patient's femur 20 include a number of resected surfaces 210. Asshown in FIG. 7, the resected surfaces 210 of each condyle 202, 204include a posterior planar surface 212, a distal planar surface 214, andan anterior planar surface 216. The resected surfaces 210 also include aposterior-chamfer planar surface 218 that extends superiorly andposteriorly from the distal planar surface 214 to the posterior planarsurface 212 and an anterior-chamfer planar surface 220 that extendssuperiorly and anteriorly from the distal planar surface 214 to theanterior planar surface 216.

When the femoral trial 14 is positioned on the distal end 200 of thepatient's femur 20, the anterior fixation surface 104 of the femoraltrial 14 contacts the anterior planar surfaces 216 of the patient'sfemur 20 and the distal fixation surfaces 86 of the femoral trial 14contacts the distal planar surfaces 214 of the patient's femur 20.Similarly, posterior-chamfer fixation surface 96 of the femoral trial 14contacts the posterior-chamfer planar surface 218 of the patient's femur20. The anterior-chamfer fixation surfaces 100 of the femoral trial 14contacts the anterior-chamfer planar surfaces 220 of the patient's femur20.

Further, the posterior fixation surfaces 82 of the femoral trial 14 gripthe posterior planar surfaces 212 of the patient's femur 20 when thefemoral trial 14 is positioned thereon. As shown in FIG. 7, one or moreof the teeth 110 of the lateral posterior fixation surface 82 engageswith, or grips, the posterior planar surface 212 of the resected lateralcondyle 204. The engagement of the teeth 110 with the posterior planarsurfaces 212 secures the femoral trial 14 to the distal end 200 of thepatient's femur 20.

In addition to positioning the femoral trial 14 on the distal end 200 ofthe patient's femur 20, the surgeon may also position the tibial basetrial 16 on a surgically-prepared proximal end 230 of the patient'stibia 22. When the surgical instrument assembly 10 is fully installed,the tibial base trial 16 is secured to the surgically-prepared proximalend 230 of the patient's tibia 22, as shown in FIG. 8. The tibialbearing trial 18, including the bearing surface trial 46 and the shim48, are positioned over the post 42 of the base insert 34. The lateralcondyle surface 56 of the femoral trial 14 contacts the lateralarticular surface 52 of the tibial bearing trial 18, while the medialcondyle surface 58 contacts the medial articular surface 54. The surgeonmay then evaluate the range of motion and stability of the knee with thesurgical instrument assembly 10.

As the range of motion is evaluated, the load on the femoral trial 14translates posteriorly as the knee is moved from extension (see FIG. 8)to flexion (see FIG. 9). As the load moves posteriorly, the force normalto the posterior condyle surfaces 84 of the femoral trial 14 increases,thereby causing the teeth 110 of the posterior fixation surfaces 82 ofthe femoral trial 14 to further engage, or grip, the posterior planarsurfaces 212 of the surgically-prepared distal end 200 of the patient'sfemur 20. The engagement of one or more of the teeth 110 of the femoraltrial 14 with the distal end 200 of the patient's femur 20 retains thefemoral trial 14 on the patient's femur 20. It should be appreciatedthat in other embodiments screws or other fasteners may be insertedthrough the through-holes 90 into the femur 20 to provide additionalfixation.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. A method of trialing prosthetic components of a knee prosthesis, themethod comprising: positioning a femoral trial component on asurgically-prepared distal end of a patient's femur, the femoral trialcomponent having an articular side and a fixation side, identifying aposition of a sidewall of the femoral trial component relative to anouter edge of the surgically-prepared distal end of the patient's femur,and selecting (i) a first femoral prosthetic component if the sidewallis positioned beyond the outer edge of the surgically-prepared distalend of the patient's femur and the surgically-prepared distal end of thepatient's femur is visible through a notch defined in the sidewall, and(ii) a second femoral prosthetic component if the sidewall of thefemoral trial component is positioned within the outer edge of thesurgically-prepared distal end of the patient's femur, the first femoralprosthetic component being more narrow than the second femoralprosthetic component.
 2. The method of claim 1, further comprisingdrilling a pair of fixation holes in the surgically-prepared distal endof the patient's femur.
 3. The method of claim 1, wherein drilling thepair of fixation holes includes inserting a surgical drill into a guidehole defined in the femoral trial component.